Weaving looms with external weft reserve

ABSTRACT

A loom with weft feed by means of bobbins located outside the shed and comprising at least one weft-inserter at one extremity of a flexible tape formed by at least two strips as well as an upper guide and a lower guide for guiding the tape along its path outside the shed and a toothed rotary system engaged with perforations of the tape in order to impart a reciprocating movement to said tape, wherein at least the strip or strips of the tape other than the inner strip are engaged with the toothed rotary system solely in the zones of the upper and lower guides so that each of said strips forms a floating loop between the outer extremities of said guides at a distance from said toothed rotary system, the successive strips being engaged over the teeth of the rotary drive system in such manner as to ensure that the perforations formed in the loops of successive strips as considered from the interior towards the exterior should increase in number between two teeth which are located respectively in said two zones.

United States'Patent Dewas [s41 WEAVING LOOMS WITH EXTERNAL WEFI RESERVE [72] lnventor: Raymond Dews, 120 Boulevard de v Saint Quentin, Amiens, France 221 Filed: May 28, 1970 [21] Appl. No.: 41,269

301 Foreign Application m Primary Examiner-Henry S. Jaudon Attorney-Richards and Geier [15] 13,682,204 4 1' Aug. 8, 1972 [57] v ABSTRACT A loom with weft feed by means of bobbins located outside the shed and comprising at least one weft-inserter at one extremity of a flexible tape formed by at least two strips as well as an upper guide and a lower guide for guiding the tape along its path outside the shed and a toothed rotary system engaged with perforations of the tape in order to impart a reciprocating movement to said tape, wherein at. least the strip or strips of the tape other than the inner strip are engaged with the toothed rotary system solely in the zones of the upper and lower guides so that each of said strips forms a floating loop between the outer extremities of said guides at a distance from said toothed 6Clains,6lkawingi1gures Patented Aug. 8, 1972 I NV EN'TOR:

R. D e was MuJ-svQ ATTO rLN 5%5 This invention relates to looms with weft feed by means of bobbins located outside the shed and comprising at least one weft-inserter at one extremity of a flexible ribbon or tape formed by at least two superposed bands or strips and guided in its path outside the shed usually by an upper guide and a lower guide which are connected to each other by means ofv an intermediate curved guide commonly referred-to as a bow, said tape being provided with a reciprocating movement by means of a toothed rotary system which engages perforations forrned in said tape.

In conventional looms of this type, the superposed formed by the inner. strip has a distinctly greater development than the bottom of the bow and the outermost strip has a development which is-distinctly smaller than the cover of the bow, assuming that the bow is provided with a cover.

Moreover, by reason of the fact that the strips are located at a distance from each other in said curved portion of the tape path, said strips are not in rubbing strips which constitute the tape are joined together only I at the extremity on which the weft-inserter is mounted, thereby permitting said strips to carry out relative longitudinal sliding movements in the curved portions of their path.

Looms are now operated at increasingly higher running speeds and/or have overall widths which tend to become greater. Consequently, the tape is driven at very high speed and, by reason of the fact that said tape is applied against the bow and produces an action which is similar to that of a band brake, there is thus a constant increase in friction which results in corresponding heat generation, abnormal wear of the tape and loss of driving power, even when the diameter of the bow has the maximum value which is compatible with the loom.

An object of this invention is to provide a weaving loom comprising a tape transfer device which eliminates the band-brake effect produced by said tape on the bow.

To this end and in accordance with the invention, at least the tape strip or strips of the tape other than the inner strip are engaged with the toothed rotary system solely in the zones of the upper and lower guides in order that each of said strips should form between the outer extremities of said guides at a distance from said toothed rotary system a loop which floats within the bow unit, the successive strips being engaged over the teeth of the rotary drive system in such manner as to ensure that the perforations formed in the loops of successive strips as considered from the interior towards the exterior should increase in number between two teeth which belong respectively to the two zones.

In accordance with one embodiment, all the strips of the tape are engaged with the toothed rotary system only in the zones of the upper and lower guides and are mounted so that each strip forms between the outer extremities of said guides and at a distance from said toothed rotary system a loop which progresses within the bow unit, the loop formed by the inner strip being located at a distance from the bottom of the bow and the loop of each other strip being located at a distance from the loop of the strip which is located immediately within the interior of the strip due to the fact that the perforations formed in the loops of successive strips as considered from the interior towards the exterior increase in number between two teeth which are located respectively in the two zones.

Due to this particular structure, the bank-brake action produced by the tape against the bow is eliminated. In fact, that portion of the tape which is contact with each other, with the result that the wear and .overheating which had previously resulted from said rubbing contact are accordingly eliminated.

In one form of construction, the toothed rotary system is constituted by a single toothed wheel disposed in the plane of the upper and lower guides and of the tape loop.

In another form of construction, the toothed rotary system is constituted by two synchronized toothed wheels which are in meshing engagement with those portions of the tape which are located respectively in the upper and lower guides.

In accordance with an alternative form of construction comprising a single toothed wheel for displacing thetape, said tape is disposed insofar as the inner strip is concerned in meshing engagement with the toothed wheel over the entire length of the arc of contact.

A better understanding of the invention will be gained from the following description and from the accompanying drawings in which forms of construction of a weft-insertion control system in accordance with the invention are shown by way of example.

In these drawings:

FIG. 1 is a front view showing one of the tapes of a weaving loom with weft feed by means of bobbins located outside the shed as well as the guides and a first form of construction of means for displacing said tape in a reciprocating movement, the front side (with respect to the observer) having been removed FIG. 2 is a partial sectional view on a larger scale and taken along line lI-II of FIG. 1

FIG. 3 illustratesa first alternative form of construction;

FIG. 4 is a view which is similar to that of FIG. 1 and showing another form of construction FIG. 5 shows an alternative fonn of FIG. 1

FIG. 6 is a sectional view on a larger scale and taken along line VI-VI of FIG. 5.

The weft-insertion control tape 1 as shown in FIG. 1 is made up of two superposed strips 2 and 3 (shown also in FIG. 2) which are joined together only at the front end on which is mounted the weft inserter (not shown). Outside the shed, said tape passes through an upper rectilineal and horizontal guide 4 carried by the slay 5, then forms at the exterior a loop extending approximately over a half-circumference and finally passes into a lower rectilineal and horizontal guide 6 so as to be brought back beneath the machine towards the interior of this latter. Inside the shed, the tape slides within guide-blocks 7 which are placed immediately after the upper horizontal guide 4.

The toothed rotary system for displacing the tape is constituted in this example by a single wheel 8 provided with teeth 9, said wheel being located in the plane of the two guides, namely the upper guide 4 and lower guide 6, and being tangent to these latter. The two strips which constitute the tape are provided with perforations-lo, the dimensions and pitch of which correspond to those of the teeth 9. The wheel 8 is carried by a shaft 11 to which is imparted a reciprocating movement of rotation. v

An intermediate curved guide or. bow 12 is located in the zoneof that portion of the tape which forrm a loop. Said bow has theshape-of a half-circumference which has the same mean diameter as that of. the toothed wheel 8 but the center of which is displaced horizontally towards the exterior with respect to the axis of the wheel 8 in order that the said bow should be clear of the teeth 9 of said wheel. .Said bow has a U-shaped cross-section which can be closed by a detachable cover 13. The progress of the two strips 2 and 3 within the bow unit which is thus formed takes place in a very special manner; The inner strip 2 is located at a distance from the bottom of the bow in'order' to ensure 4 which are identical 'and coupled respectively with the two wheels l4, 15 for displacing the tape. One of the three wheels 16, 17 or 18 is driven in a reciprocating movement of rotation by any suitable means. I

The operation of this form of construction is the same as inthe form of construction of FIG; 1. In the alternative form of FIG. 3. in which the toothed 7 wheel 8 has a particularly small diameter,- the distance that it cannot produce a bank-brake effect. This result perforations of the inner strip 2 are suitably selected and engaged by handover the teeth of the lower portionof the wheel 8 which is tangent to the lower guide 6. Theinner strip 2 is therefore engaged with the wheel 8 only in the lower and upper portions of this latter. As

far as the outer strip 3 is concerned, said strip is displaced with respect to the inner strip by either one or a number of perforations, also in said lower portion of the wheel, in order that said outer strip should be separated from said inner strip as it passes through the bow unit. Moreover, the radial depth of the bow unit must be sufficient to ensure that the outer strip 3 cannot be forcibly applied against the eccentric cover 13 of said bow unit.

During operation, the upper and lower portions of the toothed driving wheel 8 which are engaged in the corresponding upper guide 4 and lower guide 6 are in mesh with the perforations 10 of the tape and impart a reciprocating movement to this latter. The rectilineal portions of the'two superposed strips are not in rubbing or frictional contact with each other since they move exactly atthe same speed; in addition, the looped 'portions of the strips which are located within the bow unit are not in frictional contact since they are well between said wheel'and the bow 12 is greater with the result that the radius of the bow can remain sufficiently long, thereby obviating the need for a radius of curvature of the strips which might proveunsuitable for their particular structure. The lower guide 6 is accordingly inclined upwards and towards the interior of the machine in order to remain tangent to the wheel 8 and the bow 12. The portion l9 of-the lower guide 6 which immediately follows the wheel 8's not rectilineal but has a very substantial radius of curvature, with the result that friction between the strips as'well as friction between the strips and said guide are negligible, particularly due to the fact-that portion'of the tape is not subjected to the influence of inertia of theweft-insetter. I

' In order to pass the lower guide beneath the loom at the most favorable height, it is also possible to adopt separated from each other, this result being achieved formed by an assembly of two smaller toothed wheels l4, 15 having the same pitch and tangent respectively to the two guides at the same locations, the teeth of said smaller wheels being in mesh with the perforations 10 r of the two strips of the tape under the conditions explained in the foregoing. These two toothed wheels are driven in a reciprocating movement of rotation in perfect synchronism by any suitable transmission means as represented diagrammatically in thisexample by an intermediate toothed wheel 16, said wheel being engaged simultaneously with two other toothed wheels 17, 18

In the alternative form of 5, the inner strip 20f the tape which, in this example, is constituted by two superposed strips 2 and 3, is engaged with the toothedwheel 8 not only in the zone of the upper guide4 and in the zone of the lower guide 6 but over the entire lenghtv of the arc of-contact' between said wheel and said tape, namely over a half-circumference in this example. On the contrary, the outer strip 3 is engaged with the toothed wheel 8 only in the zones of said guides (see also FIG. 6). The number of perforations between two 3 wheel teeth located respectively, in the zones of the upper guide 4 and lower guide 6 is greater in the case of the strip 3 than in the case of the band 2. Reference 0 designates the center of the bow 12, reference 01 designates the center of the outer strip 3 of the tape and 02 designates the center of the cover 13.

The operation of this alternative form of construction is the same as has been described with reference to FIG. 1.

It will be understood that the invention is not limited to the embodiments which have been described with reference to the accompanying drawings and which have been given solely by way of example without any implied limitation; depending on the applications which are contemplated, any number of modifications may accordingly be made without thereby departing either from the scope or the spirit of the invention.

and guide blocks 7.

What is claimed is i l. A guide for a weft inserting control tape, said tape consisting of at least two flexible super imposed perforated strips, all perforations being equally spaced longitudinally said strips, an upper guide for said tape having an outer end, a lower guide for said tape located under said upper guide and having an outer end, said tape extending through the lower guide, beyond the outer end thereof, into and through the upper guide, forming an outwardly flexed loop composed of an inner strip portion and an outer strip portion between said guides, a toothed rotary system having teeth in engagement with the perforations of each of said strips and located in the vicinity of the outer ends of said guides for reciprocating the tape, the outer strip portion having at least one more perforation in the loop portion thereof than does the inner strip portion.

2. The combination of claim 1, wherein said lower guide is inclined.

3. The combination of claim 1- further comprising toothed rotary system is constituted by a single toothed wheel.

4. The combination of claim 3 wherein the inner strip of the tape is disposed in meshing engagement over the entire length of the periphery of the toothed wheel which extends between the upper and lower guides.

5. The combination of claim 1 further comprising toothed rotary system is constituted by two toothed wheels which are respectively engaged with those portions of the tape which are located respectively within the upper and lower guides, said two wheels being coupled with each other, by positive transmission means.

6. The combination of claim 1, further comprising a hollow bow connecting the outer ends of said upper and lower guides, said bow having an inward and an outward curved wall located some distance away from said inner and outer strip portion respectively. 

1. A guide for a weft inserting control tape, said tape consisting of at least two flexible super imposed perforated strips, all perforations being equally spaced longitudinally said strips, an upper guide for said tape having an outer end, a lower guide for said tape located under said upper guide and having an outer end, said tape extending through the lower guide, beyond the outer end thereof, into and through the upper guide, forming an outwardly flexed loop composed of an inner strip portion and an outer strip portion between said guides, a toothed rotary system having teeth in engagement with the perforations of each of said strips and located in the vicinity of the outer ends of said guides for reciprocating the tape, the outer strip portion having at least one more perforation in the loop portion thereof than does the inner strip portion.
 2. The combination of claim 1, wherein said lower guide is inclined.
 3. The combination of claim 1 further comprising toothed rotary system is constituted by a single toothed wheel.
 4. The combination of claim 3 wherein the inner strip of the tape is disposed in meshing engagement over the entire length of the periphery of the toothed wheel which extends between the upper and lower guides.
 5. The combination of claim 1 further comprising toothed rotary system is constituted by two toothed wheels which are respectively engaged with those portions of the tape which are located respectively within the upper and lower guides, said two wheels beinG coupled with each other by positive transmission means.
 6. The combination of claim 1, further comprising a hollow bow connecting the outer ends of said upper and lower guides, said bow having an inward and an outward curved wall located some distance away from said inner and outer strip portion respectively. 